Micro-interconnects (micro-wirings) in the manufacture of semiconductor apparatuses are usually formed by utilizing film deposition of an insulating film such as SiO2 by a sputtering apparatus or CVD apparatus and isotropic or anisotropic etching of Si or SiO2 by an etching apparatus. Generally, these apparatuses utilize a plasma discharge to improve film deposition rate and etching performance. For example, a plasma etching apparatus is used as an etching apparatus.
As a dry etching process which uses a plasma etching apparatus, for example, a method is known which conducts plasma etching for micro-fabrication of Si and a dry etching process of various thin films such as an insulating film, an electrode film and a wiring film deposited on a substrate during manufacture of a semiconductor.
Plasma etching is conducted as follows for example. First, a plurality of Si substrates are mounted on a surface of a lower electrode of upper and lower electrodes arranged so as to face each other in a chamber of a dry etching apparatus. Next, fluorine (F)-based gas such as CF4 or chlorine (Cl)-based gas such as Cl2 is introduced between the mounted substrates, and a plasma discharge is conducted between the electrodes to generate fluorine-based plasma or chlorine-based plasma. Then, the thin films formed on the substrates is dry-etched with active ions and radicals produced in the generated plasma to finish the process of plasma etching.
When thin films made of SiO2, Si3N4, Poly-Si and the like on a Si substrate are plasma-etched, plasma components and a material to be etched react with each other to produce reaction products such as SiF4 and fluorocarbons. Most of the reaction products are discharged out of the chamber in a gaseous state by an exhaust pump, and part of the reaction products is deposited in the chamber in a solid state to form adherent films. It is preferable that the adherent films made of reaction products are removed.
Therefore, a process has been known which discharges the reaction products (adherent films) adhering to an inside of the chamber out of the chamber by conducting dry etching using fluorine-based plasma or chlorine-based plasma in order to remove the reaction products. The dry etching, which is a process intended to remove the reaction products (adherent films), is performed by generating fluorine-based plasma or chlorine-based plasma under gas conditions different from those for dry etching of the thin films and the like described above.
However, when the reaction products constituting the adherent films are fluorocarbon-based etching products, the reaction products do not react sufficiently with fluorine-based plasma or chlorine-based plasma, and therefore the reaction products remain in the chamber. Therefore, when the remaining adherent films peel off and get mixed in the substrate, this could cause pattern defects or reduce yields.
Thus, conventionally, with respect to those components of the plasma etching apparatus which are irradiated with plasma, including the chamber, a film with high plasma resistance and corrosion resistance is formed on a surface of a base material to prevent production of reaction products. As such films, a film made of an yttrium oxide (Y2O3) and a film made of aluminum oxide (Al2O3) are known. These films are effective in curbing generation of reaction products and preventing component damage caused by plasma attacks.
For example, Japanese Patent No. 4084689 Specification (Patent Document 1) describes an Y2O3 film obtained by heat-treating a Y(OH)3 sol solution applied to a base material, and Japanese Patent Laid-Open No. 2006-108178 (Patent Document 2) describes an Al2O3 thermally sprayed film.